The purpose of this project is three fold: 1. The subunit structure of Crotalus adamenteus snake venom NGF complex will be defined. A comparison will be made between the Crotalus NGF complex and the male mouse submaxillary gland 7S NGF. The active beta subunit of Crotalus NGF will be characterized and its NH3 COOH terminus sequence determined. 2. The response of the human neuroblastoma cell lines IMR-32 and SK-N-SH to NGF will be investigated at a morphological and biochemical level. 3. The regulation of the synthesis of NGF in the rat glioma cell line C-6 and the mouse sarcoma cell line S-180 by steroids and other hormones will be studied.